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Progress in understanding algal bloom-mediated fish kills: the role of superoxide radicals, phycotoxins and fatty acids

Citation

Dorantes Aranda, JJ and Seger, A and Mardones, JI and Nichols, PD and Hallegraeff, GM, Progress in understanding algal bloom-mediated fish kills: the role of superoxide radicals, phycotoxins and fatty acids, PLoS ONE, 10, (7) Article e0133549. ISSN 1932-6203 (2015) [Refereed Article]


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Licensed under Creative Commons Attribution 4.0 International (CC BY 4.0) http://creativecommons.org/licenses/by/4.0/

DOI: doi:10.1371/journal.pone.0133549

Abstract

Quantification of the role of reactive oxygen species, phycotoxins and fatty acids in fish toxicity by harmful marine microalgae remains inconclusive. An in vitro fish gill (from rainbow trout Oncorhynchus mykiss) assay was used to simultaneously assess the effect in superoxide dismutase, catalase and lactate dehydrogenase enzymatic activities caused by seven species of ichthyotoxic microalgae (Chattonella marina, Fibrocapsa japonica, Heterosigma akashiwo, Karenia mikimotoi, Alexandrium catenella, Karlodinium veneficum, Prymnesium parvum). Quantification of superoxide production by these algae was also performed. The effect of purified phycotoxins and crude extracts was compared, and the effect of fatty acids is discussed. The raphidophyte Chattonella was the most ichthyotoxic (gill cell viability down to 35%) and also the major producer of superoxide radicals (14 pmol cell-1 hr-1) especially after cell lysis. The raphidophyte Heterosigma and dinoflagellate Alexandrium were the least toxic and had low superoxide production, except when A. catenella was lysed (5.6 pmol cell-1 hr-1). Catalase showed no changes in activity in all the treatments. Superoxide dismutase (SOD) and lactate dehydrogenase exhibited significant activity increases of ≤23% and 51.2% TCC (total cellular content), respectively, after exposure to C. marina, but SOD showed insignificant changes with remaining algal species. A strong relationship between gill cell viability and superoxide production or superoxide dismutase was not observed. Purified brevetoxins PbTx-2 and -3 (from Karenia brevis, LC50 of 22.1 versus 35.2 μg mL-1) and karlotoxin KmTx-2 (from Karlodinium; LC50 = 380 ng mL-1) could almost entirely account for the fish killing activity by those two dinoflagellates. However, the paralytic shellfish toxins (PST) GTX1&4, C1&C2, and STX did not account for Alexandrium ichthyotoxicity. Only aqueous extracts of Alexandrium were cytotoxic (≤65% decrease of viability), whereas crude methanol and acetone extracts of Chattonella, Fibrocapsa, Heterosigma, Karlodinium and Prymnesium decreased cell viability down to 0%. These and our previous findings involving the role of fatty acids confirm that superoxide radicals are only partially involved in ichthyotoxicity and point to a highly variable contribution by other compounds such as lipid peroxidation products (e.g. aldehydes).

Item Details

Item Type:Refereed Article
Keywords:fish killing algal blooms
Research Division:Biological Sciences
Research Group:Plant Biology
Research Field:Phycology (incl. Marine Grasses)
Objective Division:Animal Production and Animal Primary Products
Objective Group:Fisheries - Aquaculture
Objective Field:Fisheries - Aquaculture not elsewhere classified
Author:Dorantes Aranda, JJ (Dr Juan Dorantes Aranda)
Author:Seger, A (Mr Andreas Seger)
Author:Mardones, JI (Mr Jorge Mardones)
Author:Nichols, PD (Dr Peter Nichols)
Author:Hallegraeff, GM (Professor Gustaaf Hallegraeff)
ID Code:101987
Year Published:2015
Funding Support:Australian Research Council (DP130102859)
Web of Science® Times Cited:11
Deposited By:IMAS Research and Education Centre
Deposited On:2015-07-22
Last Modified:2016-04-19
Downloads:157 View Download Statistics

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